1. Field of the Invention
The present invention relates to an assembly for orienting a workpiece relative to predetermined orthogonal references outside the operating area of a machining apparatus.
2. Description of the Prior Art
The invention has particular utility with precision machining apparatus that are able to operate on only one workpiece at a time. With such machines, it is desirable to minimize the down time required for removing a finished work and positioning a new blank into the machine.
To help diminish the above down time, it has been customary to provide a workpiece presetting station outside the machining apparatus. Thus, while the apparatus is operating on one workpiece, a second workpiece is being secured and oriented with a duplicate set of machine tool clamping mechanisms. When the changeover time occurs, it is then a simple matter to disconnect the first clamping mechanism from the machine and reconnect the duplicate mechanisms.
In the past, the workpiece was preset by precisely fixing a rail along a predetermined axis of a large, but movable, reference block. An adaptor was then used to interconnect the rail with a vise. The vise, in turn, held the workpiece.
To orient the workpiece along each orthogonal axis, the large block itself is set upon its side for one coordinate, its end for another and its bottom for another. In some cases, additional support blocks were required to uphold large overhanging workpieces.
In each position, a dial indicator is used in conjunction with adjustment means on the adaptor to obtain the desired alignment of the workpiece. It is critical that each side of each block have exact flat orthogonally aligned reference surfaces. Also, the underlying table supporting the blocks must be flat, level and absolutely clean.